Israeli scientist proposes massive space sunshade to cut global temperatures by 1.5ºC
Yoram Rozen, head of Technion’s Space Research Institute, seeks $15 million to launch prototype; ‘If we can’t show that it can work technologically, then nobody else will do it”
Sue Surkes is The Times of Israel's environment reporter
An Israeli scientist is seeking $15 million to prove the technology for a potential huge sunshade that would block two percent of the sun’s radiation and bring global average temperatures down by some 1.5ºC (2.7ºF) within 12 to 18 months.
Throughout human history, there has generally been a balance between the sun’s heating of the Earth and the planet cooling by radiating heat back into space. However, humankind’s increasing emission of greenhouse gases since the Industrial Revolution has limited the Earth’s ability to cool itself.
Prof. Yoram Rozen and his team at the Technion’s Asher Space Research Institute in northern Israel envision a large shade that would slow the heating of Earth.
The idea would be to launch a 2.5 million-ton blanket, a distance of 1.5 million kilometers (93.2 million miles) into space, to a specific zone where the effects of gravitational pressure and solar winds would be minimal.
The shade would move with the Earth as it rotates around the sun, mainly above equatorial areas. The opaque blanket would be made of a thin, reflective material already used in solar propulsion sails in space. It resembles the blankets sometimes seen wrapped around migrants on boats when they reach European shores.
Rozen, who also teaches physics at the Technion and performs research at CERN, the prestigious European Laboratory for Particle Physics near Geneva, said the shading would barely be felt on Earth. The plan was to reduce radiation by just 2%.
“It’s not like when a cloud goes between you and the sun. It’s more like the difference in light between noon and 2 p.m.,” Rozen said.
He added that according to the data, the effects on biology and photosynthesis would be “negligible.”
Asked what the downsides of the project were, he answered, “The cost.”
The full project is estimated at $30 trillion — more than the US GDP but less than the $38 trillion estimated in annual damages due to global warming by mid-century, according to a recent study in the prestigious scientific journal Nature.
In the meantime, Rozen wants to create a prototype shade, the size of a classroom blackboard, attached to “a brain,” to prove that the technology for the project, which he calls Cool Earth, is workable in space.
“It will need a control unit,” Rozen explained, “a spacecraft that will rotate it and decide where it is and when it should turn on and off.”
The satellite would send pictures to Earth of the shade’s orientation in different positions at different times.
Rozen said the prototype could be launched within three to four years of a confirmed budget. However, the funds are not yet available.
The sunshade was “not my idea,” Rozen told The Times of Israel. “It’s been around for about 15 years. There are some papers about such solutions. But we’re the ones trying to turn it into reality. If we can’t show that it can work technologically, then nobody else will do it.”
He emphasized that if the technology could be proven, scientists would let entrepreneurs take it forward.
“As an academic institution, we’re interested in doing the first step,” he said.
If the technology is proven and $30 trillion can be found, the shade would have to be taken to space in stages, Rozen said, possibly in 10 square kilometer (3.85 square mile) sections. “Squares tie together better than circles,” he noted.
He noted that once the shade is deployed, it would take up to 18 months for the Earth to cool by 1.5 degrees Celsius.
Once that goal is reached, a few shade sections would be retained to maintain the temperature. The rest could be floated off toward the sun.
Rozen said the Asher Institute had worked with the United Arab Emirates National Centre for Space and Science. The UAE had planned to present the project at COP28 in Dubai, which was held in November-December last year.
But the Gulf country halted that cooperation in October following the start of Israel’s war against Hamas in the Gaza Strip after Hamas’s October 7 attacks
Rozen explained that while reducing global warming emissions was essential, that would not be enough to reverse the havoc global warming is wreaking on Earth, with extreme weather events, droughts, flooding, and wildfires.
Removing emissions would slow the rate of temperature increase, but it would continue to rise for a long time before starting to come down.
